1. Field of the Invention
The present invention relates to a primer composition for a cured silicon-containing surface and its uses. In particular, the present invention relates to a primer composition for a cured silicone elastomer surface and its uses.
2. Descriptions of the Related Art
Currently, a lot of the commercial products use silicon-containing materials, in which the silicone elastomer is one of the widely used materials. The silicone elastomer is generally applied on various fields, such as insulation tubes of electric equipments, pacifiers, injection pipes, drying agents, dust shields, components of food producing machines, soft molds used in industries, adhesives, sealing gels for glass or aluminum doors and windows, and the like. The silicone elastomer, also known as polymerized siloxane, is substantially composed of organic monomers and inorganic monomers. Its chemical formula is [R2SiO]n, in which each R independently represents methyl, ethyl, or phenyl.
The cured silicon elastomer has properties of stability (low reactivity), low toxicity, weatherability, water resistance, acid and alkali resistance, and electrical specification and is not easily yellowed or brittled by the irradiation of the UV light. Therefore, the cured silicone elastomer has been widely used in many industries. In particular, the cured silicone elastomer has became an important material in the biotechnical and cosmetic industries, such as medical pipes, artificial cartilages, artificial chins, artificial breasts, and replicas used in odontology.
The cured silicone elastomer can usually be classified into two types: liquid silicone elastomer and solid silicone elastomer. The liquid silicone elastomer, also known as room temperature vulcanization (RTV) silicon elastomer, is produced primarily by performing a condensation of the silane monomers through the moisture in the air at room temperature. The solid silicone elastomer, also known as high temperature vulcanization (HTV) silicone elastomer, is vulcanized primarily in two manners. The first manner is the addition vulcanization, which performs a crosslinking reaction of the silane monomers to form a polymer in the presence of a catalyst such as platinum. The second manner is the radical vulcanization, which induces a polymerization through the radicals of peroxides at a high temperature and vacuum to form a polymer of silicone elastomer.
There are only few functional groups in the cured silicone elastomer and most functional groups are C—H single bonds. The surface free energy of the cured silicone elastomer is relatively low, and therefore, the adhesive cannot be easily adhered thereon. It is hard to bond the cured silicone elastomer with other materials using an adhesive. In the past, the cured silicone elastomer has been fixed on other materials mainly via stitching. Using this manner, however, holes will be produced on the cured silicone elastomer, and thus destroys its structure and influences the overall look. The reactive silicone elastomer hot glue (product name: HM-2500) produced by Dow Corning Company is used to attach the cured silicone elastomer. However, the bonding effect provided by HM-2500 hot glue for the cured silicone elastomer cannot be well satisfied and will decrease over time.
Given the above, although the cured silicone elastomer itself has excellent properties such as weatherability, water resistance, acid and alkali resistance and the like, its poor adhesion effect of the adhesive will greatly decrease its practicability. There is a need for effectively attaching a cured silicone elastomer on other materials to improve the applicability of the cured silicon elastomer. Therefore, the subject invention provides a primer composition for improving an adhesion of an adhesive to a cured silicon-containing surface to improve the availability of the cured silicon-containing material.